This invention relates to a discharge drain assembly for use in the outlet of a sink.
The present invention is an improvement over that disclosed and claimed in Canadian Pat. No. 882,283 of Frank E. Dudas, et al issued Sept. 28, 1971. That Patent discloses a discharge drain assembly which includes a drain body adapted to be attached at its upper end to a drain opening in a sink and at its lower end to a waste pipe. A plug assembly is adapted to fit loosely in the drain body for movement between an open position in which waste water is strained as it passes to the waste pipe, and a closed position in which water is sealed in the sink. The plug assembly includes a strainer, a washer and a spindle which has protrusions at its lower end for cooperating with the drain body to hold the plug assembly in the open position. The strainer is located on the spindle above a resilient washer and an integral shoulder on the spindle such that the washer also seals the sink when the plug assembly is in the closed position.
The assembly according to the Patent has a hollow knob and the structure of the strainer is such that there may be difficulty in "finding" the strain position. Furthermore, the method of assembly requires undesirably close tolerances on the rubber washer.
A combined strainer-basket and drain valve is disclosed in U.S. Pat. No. 2,512,867 of K. R. Marcussen issued June 27, 1950. Unlike the present invention, it does not have a unitary knob and strainer but utilizes a separate cap. The plug-body includes a post or shank over which the cup is fitted. A joint is left between the cap and the strainer in which dirt can collect. The cap is a force fit on the plug-shank and it can be disassembled for cleaning the structure. Also, the positioning lugs are straight so that it is necessary to lift the strainer to be able to bring it to the open position. In the present invention, the strainer is turned in one direction to close it and in the other direction to open it. Furthermore, the strainer assembly includes lugs or legs structured so as to prevent rotation beyond the open position, thus alleviating the "finding" problem.
Gleason U.S. Pat. No. 2,500,674 issued Mar. 14, 1950 discloses a sink drain valve having lugs or legs with cam surfaces, but not for rotation along a short cam surface in the closing direction. It is necessary to lift a knob to permit the lugs or legs to clear the spider in the drain body. The stopper is shown to be solid whereas the stopper (rubber washer) used in the present invention has a flexible "skirt" for better sealing action.
Another type of drain assembly is shown in the Link U.S. Pat. No. 2,569,615 issued Oct. 2, 1951. One embodiment does not have legs which rest on the spider legs but rather has a central lifter stem which fits in a central hole in the spider. Another embodiment disclosed does show lugs or legs but they are straight-sided so that it is necessary to lift the strainer in order to turn it to the open position. There is obviously still a "finding" problem.
Fredrickson U.S. Pat. No. 2,263,537 issued Nov. 18, 1941 shows an apparently solid stopper with ribs on the underside and lugs on the upperside which hold the strainer. Again, in this structure, it is necessary to lift as well as rotate the strainer in order to open the drain.
In many known structures, the plug assembly is held in the closed position essentially by gravity and if conditions are not ideal, the plug leaks. To correct this defect, the plug assembly of the present invention includes legs depending from a spindle and having a length such that they "lock" the assembly in place in the seal position by their contact with the bridges of the spider at the bottom of the drain body.
To correct the "finding" fault for the strain position, the legs extend even further so that when the plug assembly is turned counter-clockwise from the seal position to the strain position, there is a positive stop achieved when the bottom part of the leg strikes a bridge between the holes of the spider at the bottom of the sink basket. To ensure that the plug assembly remains in the strain position, each leg has a seat to fit each bridge of the spider. Thus, the invention provides a plug and strainer that provides the user with ease of use, notably in the area of "self-location" to strain or seal position, short and easy turn radius to either strain or seal position (about 1/3 revolution), positive location of strain and seal position and a plug assembly that locks in the seal position to prevent leaking.
As regards the above mentioned Canadian Pat. No. 882,283, the structure disclosed therein requires that the strainer and spindle be held together by the washer. In the present invention, the washer is held to the spindle by stretching it out into a slot in the spindle. The spindle is attached to the strainer by forcing an expandible protrusion into a hollow knob drawn in the strainer. This provides an easily assembled mechanical attachment of parts that can be disassembled for washer replacement. The invention allows for fairly broad tolerances in the parts and the chance of unintentional separation is minimized.
In the structure of the aforementioned Canadian Pat. No. 882,283, the "hardness" of the solid rubber washer tends to cause improper seating and, therefore, leaking. In the present invention, the washer has a flexible outer skirt which provides a good sealing action.
In the structure of Canadian Pat. No. 882,283, the strainer is turned to attain the locked and sealing position, but the rubber washer rubs against the steel body with some difficulty. In the present invention, the plastic spindle runs easily over the steel bridges of the spider to achieve the locked seal.
As mentioned above, the knob of the spindle of Canadian Pat. No. 882,283 is hollow and its shape is such that dirt can collect and grow in places that are difficult to clean. In the present invention the spindle is solid and has easily cleaned contours.